Carbon black pelleting agent

ABSTRACT

A carbon black pelleting agent which acts as a pelleting agent and which acts to disperse the carbon black in rubber which comprises an aqueous solution of a polyethyoxylated fatty acid.

United States Patent Frazier et a1.

[ 1 Feb. 29, 1972 1 541 CARBON BLACKPELLETING AGENT [72) Inventors:Arthur E. Frazier;- Robert E. Dollinger,

both of Borger, Tex.

[73] Assignee: Phillips Petroleum Company [22] Filed: Nov. 20,1968 211Appl. No.: 777,490

[52] (1.8. CL ..1'06/ 307, 23/314, 106/308 F, 106/308 Q, 264/117 [51]Int. Cl ..C09c 1/58 [58] Field of Search ..106/307, 308 F, 308 Q;23/314; 264/ 1 17 [56] References Cited UNITED STATES PATENTS 2,050,1938/1936 Park 106/307 Primary Examiner-James Poer Assistant Examinerl-l.M. S. Sneed Attorney-Young and Quigg [57] ABSTRACT A carbon blackpelleting agent which acts as a pelleting agent and which acts todisperse the carbon black in rubber which comprises an aqueous solutionof a polyethyoxylated fatty acid.

5 Claims, No Drawings CON BLACK PELLETING AGENT This invention relatesto dispersing agents.

In one of its more specific aspects, this invention relates to pelletingagents having dispersion properties.

Carbon black is generally pelleted prior to bagging for the purpose ofsimplifying handling. Various agents facilitate the pelleting operation,such agents improving the agglomeration. Generally, these agents have noeffect in the rubber in which the carbon black may be subsequentlyblended as a reinforcing agent.

There has now been discovered a class of compounds which facilitate thepelleting operation-and, at the same time, affect the carbonblack whenblended in rubber. This efiect makes these compounds particularlyvaluable as pelleting agents.

According to this invention there is provided an improved agent for thepelleting of carbon black which comprises an aqueous solution of fromabout 0.05 to about 5 percent of polyethyoxylated fatty acid.

Accordingly, it is an object of this invention to provide an improveddispersing agent.

It is another object of this invention to provide a pelleting agent forcarbon black and for facilitating the dispersal of carbon black inrubber compounds.

The polyethyoxylated fatty acids of this invention have the generalformula in which x, the moles of ethylene oxide, varies from about toabout 15. Such fatty acids usually have a molecular weight from about500 to about 1,000, a specific gravity from about 0.9 to about 1.1 andmay be either solids or liquids. The alkyl radical, R, is generallyderived from stearic acid, oleic acid, or rosin fatty acids.

Some of the more effective fatty acids are commercially known asEthofats. Ethofat 60/20, derived from stearic acid, is particularlyeffective. This compound has an average molecular weight of about 720,contains moles of ethylene oxide, has a specific gravity of about 1 andis a soft paste at 25 C.

Another of these compounds is commercially known as Ethofat 0/15. Itcontains 5 moles of ethylene oxide; its molecular weight is about 505;it has a specific gravity of about 1 and is a liquid at 25 C. In thiscompound, the source of the alkyl radical is oleic acids.

Still another of these compounds is Ethofat 242/25 in which there aremoles of ethylene oxide, its average molecular weight being about 975,its specific gravity being about 1.08, the material being liquid at 25C. In this compound the source of the alkyl radical is rosin fatty acid.

Other commercially available Ethofat compounds which have been foundsuitable are Ethofat 0/20 and Ethofat 142/20.

When compounds such as these Ethofats are used in pelleting, they areadded to the carbon black in amounts from about 0.05 to about 5 percentof the weight of the wet pellet prior to drying, the drying removing theprincipal portion of the moisture incorporated in pelleting. Preferably,the additives are added in amounts from about 0.1 to about 0.75 weightpercent of the pellet on a wet basis. Accordingly, the additives will becontained in the final carbon black pellet in an amount from about 0.1to about 10 percent of the weight of the pellet on a dry basis.

These compounds may be added directly to any medium, such as water,which is used in pelleting the carbon black or may be added with any ofthe conventional pelleting agents such as molasses, nitric acid and thelike. Generally, these additives are effective as a component of anycommercial pelleting liquid.

The addition of these compounds can be made directly to the rubber inwhich the carbon black is dispersed, the dispersing agent then beingadded in approximately the same percentages as used in the pelletingprocess. These compounds can be used to pelletize all blacks includingchannel,

furnace and thermal blacks; however, their effect may vary from black-to black. These agents particularly facilitate dispersion of thoseblacks difficult to disperse, that is, the low structure blacks.

in order to evaluate the additives concerned herein, various rubberformulations were made to which were added dried carbon black pellets,pelleted by the use of additives. Evaluations between these additivesand other additives were made by the photographic technique described byN. A. Stumpe, Jr. and H. E. Railsback in Carbon BlackDispersion-Photographic Technique and Rating System," RUBBER WORLD 151,No. 3, 41 (1964). The five standard stocks were mixed in the B-Banburymixer using the following recipes:

SBR-ISOO 100 100 100 100 100 Philrich 5' 0 15 30 45 60 Zinc Stearate 4 44 4 4 Flexamine l l 1 1 l Sulfur 1.67 1.92 2.17 2.42 2.67 NOBS Special 11.15 1.30 1.45 1.60

'TrademarltPhilips Petroleum Company In the above formulation, thestyrene-butadiene rubber 1500 (SBR-lSOO) was a random copolymer rubber,well known in the art. Zinc stearate was used instead of zinc oxide toeliminate any effects of the latter on dispersion. The NOBS Special isN-oxydiethylene-2-benzothiazyl sulfenamide.

The Flexamine of the above formulations is a physical mixture comprisedof about 65 percent of a complex diarylamineketone reaction product andabout 35 percent of N,N'- diphenyl-p-phenylenediamine.

In each instance, a carbon black, manufactured by the furnace process,was pressed to a density of about 12 to 13 pounds per cubic foot andpelleted, the additive having been added to the water employed inpelleting to the extent hereinafter indicated. After pelleting, thepellets were dried to water contents from about 0 to about 0.2 part byweight in. about 56 parts per carbon black, depending upon the amount ofwater used in the pelleting process. Normally, the amount of water inthe undried pellet, as formed, was from about 30 to about 60 weightpercent of the pellet, depending upon the type of black involved.

To prepare the various dispersions, 1752 parts by weight of black wereslowly added to 35 parts by weight of each gum masterbatch in aBrabender Plastograph, operated at 30 r.p.m. and C. Addition wascompleted in about 1 minute after which the ram was inserted in themixing head and the batch was mixed for about 7 minutes at 70 r.p.m.

The batch was dumped to form a rectangular slab which was cured for 30minutes under 153 C. The dispersion rating was then determined by theaforementioned photographic method.

Each dispersion was rated by four observers and the results wereaveraged and plotted, relating rating to the amount of oil added. Fromeach plot, the amount of oil added to give a dispersion rating of 6.6was read, this rating being intermediate between good and fair, and ofacceptable commercial quality, thus being indicative of the amount ofoil which could be tolerated in the batch.

Comparative results are shown in Table 1 below. Each additive has beenassigned an oil tolerance rating determined by the above method, thehigher the oil tolerance rating, the better the dispersion capabilitiesof the additive.

3 Ethotat' 242/25 0.2 44 36 4 Coagulant Aid no. 225 0.2 44 28 5 Cat-Flo:0.05 44 26 6 Cal-Floc 0.2 44 29 7 Distilled Water 0 52 35 coagulant Aid,No. 2251Cnlgon Corp., Pittsburgh, Pa.

Cat-Floc: Organic Polymeric Cationic coagulant-Calgon Corp., Pittsburgh.Pa.

The above data include results using water for pelleting and using twoother commercially acceptable pelleting agents, Cat-Floc and coagulantAid No. 225. The oil tolerance rating with water, alone, provides thebasis of evaluation. While the commercial agents show a definiteimprovement in the oil tolerance rating, the use of the polyethyoxylatedfatty acids show a still further improvement thereover.

inasmuch as these data show improved results with distilled ordemineralized water, alone, over undistilled water, alone, Samples No. 7and 1, it is expected that the use of the polyethyoxylated fatty acidsin distilled water solutions would show a still further improvement inoil tolerance rating. Similarly, the addition of the polyethyoxylatedcompound to any pelleting agent which improves oil tolerance rating,would be expected to impart still further improvement to the resultingsolution.

While not shown by these data, the use of the additives, in allinstances, resulted in carbon black pellets commercially acceptable inall aspects.

It will be understood that various modifications can be made to theinvention and its use as disclosed herein. However, such are to beconsidered as within the scope of the invention.

What is claimed is:

l. A carbon black pelleting agent consisting of water and from about 0.5to about 5 weight percent of a polyethoxylated fatty acid of the generalformula ethylene oxide as represented by x is within the range of fromabout 5 to about 15.

2. The pelleting agent defined in claim 1 in which said fatty acid has amolecular weight in the range of from about 500 to about 1,000.

3. The additive defined in claim 1 in which said fatty acid is presentin said agent in an amount in the range of from about 0.05 to about 5weight percent.

4. Carbon black in pelleted form, said pellet consisting ofsubstantially dry carbon black and the polyethoxylated fatty aciddefined in claim 1, said fatty acid being present in said pellet in anamount within the range of from about 0.1 to about 10 weight percent ofsaid carbon black.

5. Carbon black in pelleted form, said pellet consisting ofsubstantially dry carbon black, molasses and the polyethoxylated fattyacid defined in claim 1, said fatty acid being present in said pellet inan amount within the range of from about 0.] to about 10 weight percentof said carbon black.

2. The pelleting agent defined in claim 1 in which said fatty acid has amolecular weight in the range of from about 500 to about 1,000.
 3. TheaddItive defined in claim 1 in which said fatty acid is present in saidagent in an amount in the range of from about 0.05 to about 5 weightpercent.
 4. Carbon black in pelleted form, said pellet consisting ofsubstantially dry carbon black and the polyethoxylated fatty aciddefined in claim 1, said fatty acid being present in said pellet in anamount within the range of from about 0.1 to about 10 weight percent ofsaid carbon black.
 5. Carbon black in pelleted form, said pelletconsisting of substantially dry carbon black, molasses and thepolyethoxylated fatty acid defined in claim 1, said fatty acid beingpresent in said pellet in an amount within the range of from about 0.1to about 10 weight percent of said carbon black.